A power converter for driving a motor is mounted on a hybrid car and an electric car.
The power converter drives the motor by converting DC power supplied from a battery into AC power, and also converts AC power regenerated by the motor into DC power and stores the DC power in a power storage apparatus.
The power converter includes a power module in which a power semiconductor module including a semiconductor device is stored in a metal case. The power semiconductor module includes the semiconductor device and a radiation conductor plate supporting the semiconductor device, and has a structure in which the semiconductor device and the conductor plate are integrated by covering, with a resin material, peripheral side surfaces of the semiconductor device and the conductor plate. The metal case stores the power semiconductor module in close contract with the conductor plate.
As such a structure, a structure is known in which an adhesive insulating layer is formed between an inner surface of the metal case and an outer surface of the conductor plate of the power semiconductor module for improving insulation performance and heat conductivity (see PTL 1, for example).